Observation and description of phonon interactions in molecular dynamics simulations

Three-phonon interactions are identified and analyzed in nonequilibrium molecular dynamics simulations of the Lennard-Jones face-centered cubic crystal. The small simulation cells studied and the classical nature of the simulations lead to a different description of the phonon transport than the quantum-particle model. The selection process is strictly governed by the mode wave vectors. In determining the strength of an allowed interaction, one must consider the mode polarizations and frequencies—the latter in the context of internal resonance. The results are consistent with intrinsic scattering rates calculated directly from the Lennard-Jones potential.